Zillow grows database, boosts 'Zestimate' accuracy
Site's margin of error shrinks to 8.5% nationwide
By Inman News, Tuesday, June 14, 2011.
Property search and valuation site Zillow has expanded its property database and improved the accuracy of its "Zestimate" home valuations, the site announced today.
Zillow has added more than 25 million new Zestimates to its database, bringing its coverage total to about 100 million homes, or more than three-quarters of all homes in the country, the site said.
A new algorithm takes into account user-submitted information not found in public records on more than 28 million properties, such as remodeling updates or other property details. The algorithm has improved Zillow's median margin of error to 8.5 percent nationwide from a previous error margin of 12.3 percent, the site said. The margin of error is calculated by comparing Zestimates to actual sale prices.
Zestimate accuracy varies by location. Among major metro areas, margin of error ranges from 5.5 percent in Denver to 10.5 percent in Dallas-Fort Worth.
"Zestimates are a starting point in determining a home's value," the company notes, and suggests that other data, such as "a home's value range, comparable recent sales, and current listings" can also be useful to real estate consumers.
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Submitted by Derek Eisenberg on June 17, 2011 - 10:51am.
In NJ Tax Class 2 is 2-4 family properties. Our weak classification codes do not differentiate the number of units. Try a Zestimate on a 2, 3 or 4 family in NJ. The comps are likely to be one family. Similarly, single families occasionally are comped with 2-4s.
Derek Eisenberg
http://www.mls2u.com